Atmospheric pressure and oxygen partial pressure decrease as the altitude rises. Low level of partial pressure of oxygen in inspired air results in the decrease of arterial blood oxygen partial pressure, decrease of oxygen content, and insufficient oxygen delivery to tissues. This condition, which is called hypobaric hypoxia (HH), mainly occurs in high altitude areas, and thus is also referred to as high altitude hypoxia.
Acute Hypobaric Hypoxia occurs when one reaches an area with an altitude of over 2500 meters. If one can not acclimate such an environmental change, he or she may suffer successively from High-Altitude Headache (HAH) and Acute Mountain Sickness (AMS). Moreover, AMS may further develop into High-Altitude Cerebral Edema (HACE) and High-Altitude Pulmonary Edema (HAPE). A large number of reports have showed that clinical features caused by altitude sicknesses include neurological symptoms such as headache, polylogia, insomnia, gait disturbance, impaired mental ability, somnolence, mental numbness and ataxia.
Current therapeutics for altitude sicknesses majorly was focus on the improvement of oxygen delivery, and cytokines or inflammatory responses. A representative drug of the former is acetazolamide, a carbonic anhydrase inhibitor. Exemplary drugs of the latter include glucocorticoids and some antioxidants (Wright A, Brearey S, Imray C. High hopes at high altitudes: pharmacotherapy for acute mountain sickness and high-altitude cerebral and pulmonary oedema. Expert Opin Pharmacother 2008 January; 9(1):119-27). There has been no report regarding use of a neuro-protective agent for treating altitude sicknesses.
Chinese Patent No. ZL 2010 1 0224173.3 to Sun Yat-Sen University disclosed a newly discovered neuro-protective agent, 5α-androstane-3β,5,6β-triol, having a formula of:

The present inventors surprisingly found that 5α-androstane-3β,5,6β-triol and its analogs could significantly improve the neurological scores in individuals with hypobaric hypoxia treatment and protect the brain from pathological damage caused by hypobaric hypoxia. These compounds are prospective for use in prophylaxis or treatment of altitude sicknesses caused by hypobaric hypoxia.